Resource management for real-time communication: making theory meet practice

This paper focuses on bridging the gap between theory and practice in the management of host CPU and link resources for real-time communication. Using our implementation of real-time channels, a paradigm for real-time communication in packet-switched networks, we illustrate the tradeoff between resource capacity and channel admissibility, which determines the number and type of real-time channels that can be accepted for service and the performance delivered to best-effort traffic. We demonstrate that this tradeoff is affected significantly by the choice of implementation paradigms and the grain at which CPU and link resources are multiplexed amongst active channels. To account for this effect we extend the admission control procedure for real-time channels originally proposed using idealized resource models. Our results show that practical considerations significantly reduce channel admissibility compared to idealized resource models. Further, the optimum choice of multiplexing grain depends on several factors such as resource preemption overheads, the relationship between CPU and link bandwidth, and the interaction between link bandwidth allocation and CPU bandwidth allocation.